Wax-organic extender emulsion and method for manufacture thereof

ABSTRACT

A wax-extender emulsion including a plurality of wax-extender complex particles suspended in water is described. A wax-extender complex includes a wax component, an organic extender component and a surfactant that stabilizes the wax component and the organic extender component collectively to form the wax-extender complex. The wax-extender emulsion comprises from 2 wt % to 30 wt % organic extender. During manufacturing, the organic extender and wax component are emulsified and homogenized together to produce the wax-extender emulsion. The wax-extender emulsion can be co-applied as a mixture with adhesive resin during wood-based composite manufacturing.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a National Stage application of InternationalApplication No. PCT/US2017/063654, filed Nov. 29, 2017, which claims thebenefit of U.S. Provisional Application No. 62/429,096, filed Dec. 2,2016, the entire contents of which are hereby incorporated herein byreference.

BACKGROUND 1. Technical Field Text

This disclosure relates to wood-based composites, the components used tomanufacture wood-based composites and the methods for manufacturingwood-based composites. This disclosure further relates to the use of anextended wax emulsion in manufacture of wood-based composites.

2. Background Information

Wood-based composites are generally manufactured by binding strands,particles, fibers, or furnish of one or more types of wood together withadhesive. Wood-based composites may include, but are not limited to,oriented strand board (OSB), particle board, plywood, waferboard,chipboard, medium-density fiberboard, parallel strand lumber, orientedstrand lumber (OSL), and laminated strand lumber.

Moisture durability is important for the performance of products madefrom wood-based composites. For example, moisture durability is veryimportant in densified panel products, including particleboard, fiberboard products, and oriented strand board, where product strength ishighly dependent on panel density. As a hygroscopic material, woodabsorbs moisture and swells. In densified wood-based composites, thisswelling can result in decreased mechanical integrity. For products madefrom wood-based composites, moisture-induced cyclic swelling andshrinkage can cause internal stress and potentially failure of the bondsbetween the wood strands, particles, or fibers and the adhesive holdingthe composite together. Wax can be helpful in reducing the intrinsichygroscopicity of the wood-based composite panel, thereby reducing theextent of water absorption and moisture-induced swelling. The waxcomponent is often referred to as a sizing agent.

Slack waxes and water-based wax emulsions have conventionally been addedto wood-based composite panels to improve moisture durability and tohelp lubricate wood fiber material for greater efficiency duringmanufacturing. However, adding too much wax can diminish mechanicalproperties, perhaps by causing barriers between wood and adhesiveresins.

Conventionally, wax sizing agents are sprayed or atomized into particleblenders in a similar manner as liquid and powder adhesive resins to aidwith moisture performance of the wood-based composite beingmanufactured.

However, it is inevitable that some overlap will occur between theadhesive and the wax components on some of the wood particle materials.Where this occurs, the efficacy of the adhesive resin is decreasedbecause the wax layer interferes with the direct wood/adhesive/woodinterface. To try to overcome the decrease in efficacy due to the wax,greater amounts of resin can be used in an attempt to achieve the samelevel of mechanical integrity (i.e., stiffness, bond strength, bendingstrength, etc.). To determine whether mechanical integrity hasdiminished, various methods can be used to measure performancecharacteristics of a wood-based composite. For example, moisturedurability can be evaluated by measuring thickness swell, linearexpansion, and water absorption for a wood-based composite.Additionally, mechanical strength of a wood-based composite can bemeasured parallel or perpendicular to the panel dimension, via sheartesting, and with internal bond tests.

Much of the wax used for production of wood-based composites is abyproduct of oil refining and is thus a non-renewable resource. As such,it is desirable to reduce the amount of wax used in wood-basedcomposites without sacrificing moisture durability, dimensionalstability or mechanical performance. For example, comparable moistureperformance can be achieved using wax emulsions that have a reducedamount of wax solids relative to slack wax systems, which are comprisedcompletely of molten wax. Wax emulsions use water as a delivery vehiclethereby increasing the total volume of liquid dispensed into a blenderrelative to molten slack wax. Thus, it is possible to achieve a greaterdistribution of wax solids onto wood particles or fibers. It is alsopossible to offset a portion of the total wax solids that are used inemulsion waxes using an organic extender in place of a portion of thewax solids. Using an organic extender to offset a portion of the waxsolids reduces the amount of wax used in the wood-based composite andcan aid in distributing the wax component more broadly among the woodfibers than just a reduction in wax volume or mass. Further, using anorganic extender to replace a portion of the total wax can aid incompatibilizing the dissimilar wax and resin materials, thus enablinggreater adhesive efficacy for resin droplets that overlap wax dropletson wood particle materials during production of a wood-based composite.Increased compatibility may also allow for simultaneous, co-applicationof resin mixed with extended wax emulsions, further improving both waxand resin distribution on the wood furnish.

BRIEF SUMMARY

In a first aspect of the invention, a wax-extender emulsion comprises awax-extender complex suspended in water, wherein the wax-extendercomplex comprises a wax component, an organic extender component and asurfactant. The surfactant associates with and stabilizes the waxcomponent and the organic extender component, which are closelyassociated with one another, to form the complex, wherein thewax-extender emulsion comprises from 2 wt % to 30 wt % organic extender.

In a feature of the first aspect, the wax component comprises apetroleum-based wax, a bio-based wax, a synthetic wax or mixturesthereof. With regard to this feature, the petroleum-based wax comprisesslack wax. With further regard to this feature, the slack wax comprisesbetween 5 wt % to 30 wt % oil, having a melting point below 170° F. anda flash point below 600° F. In accordance with this feature, thepetroleum-based wax further comprises oil, petrolatum, pure paraffinic,microcrystalline, scale waxes, or combinations thereof.

In an additional feature of the first aspect, the organic extendercomprises lignocelluloses, lignocellulosic agricultural residue, ligninmaterials, non-lignocellulosic agricultural materials, ligninderivatives or mixtures thereof. With regard to this feature, the ligninmaterial comprises one or more byproducts of a pulping process, whereinthe pulping process is selected from the group consisting of kraftpulping, sulfite pulping, ASAM organosolv pulping, acid hydrolysis, sodapulping, Alcell® pulping, Organocell pulping, Acetosolv pulping, andcombinations thereof. Further, regarding this feature, the ligninmaterial comprises one or more byproducts of kraft pulping.Additionally, the lignocellulosic and non-lignocellulosic agriculturalresidue comprises tree bark, wood flour, nut shells, seed hulls, corncobbs, sugar beet residuals, sugar cane residuals, wheat flour, wheatbran, corn flour, corn starch, rice flour, soy flour, or mixturesthereof.

With further regard to the first aspect, the emulsion comprises 20 wt %to 60 wt % wax component. In another feature of the first aspect, theemulsion comprises 30 wt % to 70 wt % combined wax component and organicextender.

In a further feature of the first aspect, the emulsion surfactantcomprises the reaction product of a fatty acid and a base. With regardto this feature, the fatty acid comprises a C₁₂ to C₂₂ fatty acid. Withfurther regard to this feature, the fatty acid comprises lauric acid,palmitic acid, stearic acid, behenic acid, oleic acid, linoleic acid,linolenic acid, isomers thereof or mixtures thereof. Additionally, thefatty acid may account for up to 5 wt % of the wax emulsion. Further,the base may comprise a mono-functional amine, a multi-functional amine,cyclic amine, an alkali metal salt, an alkaline earth metal salt,ammonia or combinations thereof. With further regard to this feature,the base accounts for up to 5 wt % of the wax emulsion.

In another feature of the first aspect, the wax-extender emulsionfurther comprises a defoamer and a pH modifier. With regard to thisfeature, the defoamer comprises a water-based defoamer, a silicone-baseddefoamer, a silicone-free defoamer, an oil-based defoamer, apolymer-based defoamer, or mixtures thereof. With further regard to thisfeature, the pH modifier comprises a mono-functional amine, amulti-functional amine, an alkali metal salt, an alkaline earth metalsalt or combinations thereof. In accordance with this feature, thewax-extender emulsion comprises 30 wt % to 60 wt % petroleum-based waxas the wax component and 5 wt % to 20 wt % lignin material as theorganic extender, wherein the emulsion surfactant comprises the reactionproduct of a C₁₂-C₂₀ fatty acid and a complimentary tri-functionalamine, the defoamer comprises a nonionic blend of mineral oil and silicaderivatives, and the pH modifier comprises sodium carbonate and sodiumhydroxide.

In yet another feature of the first aspect, a particle size distributioncurve for the wax-extender emulsion has a single, uniform peak. In anadditional feature of this aspect, a peak wax volatility temperature ofthe wax component in the wax-extender emulsion is higher than a peak waxvolatility temperature of a control wax emulsion utilizing the same baseslack wax material. With regard to this feature, the peak wax volatilitytemperature of the wax component in the wax-extender emulsion is betweenabout 1° C. and 40° C. higher than the peak wax volatility temperatureof a control wax emulsion utilizing the same base slack wax material.With further regard to this feature, the peak wax volatility temperatureof the wax component in the wax-extender emulsion is between about 20°C. and 40° C. higher than the peak wax volatility temperature a controlwax emulsion utilizing the same base slack wax material.

In a second aspect of the invention, a process for producing awax-extender emulsion, comprises introducing water at a temperature of35° C. to 95° C. to a vessel; introducing organic extender to thevessel; introducing components that form an emulsion surfactant to thevessel; introducing a molten wax component to the vessel; forming awax-extender emulsion by mixing the water, organic extender,surfactant-forming components, and molten wax in the vessel; andimparting a high degree of shear and mixing to the formed emulsion suchthat the molten wax and the organic extender are co-homogenized.

In a feature of this aspect, a homogenizer is used to impart a highdegree of shear and mixing on the wax-extender emulsion. In anotherfeature, the process further comprises introducing defoamer to thecontainer prior to emulsification. In yet another feature, the processfurther comprises introducing a pH modifier to the container prior toemulsification. In an additional feature, agitation is taking placeduring introduction of the water, the organic extender, the pH modifier,and the wax component. In a further feature, the organic extender isintroduced in the form of an organic extender slurry. With furtherregard to this feature, the process further comprises preparing theorganic extender slurry by combining and mixing water, defoamer, pHmodifier and organic extender thereby producing the organic extenderslurry. In addition, combining and mixing may comprise imparting highshear and mixing on the water, defoamer, pH modifier and organicextender. In an additional feature, the process further comprisescooling the wax-extender emulsion after imparting high shear and mixing.

In a third aspect of the invention, a method of simultaneouslyco-applying a mixture of a wax-extender emulsion and an adhesive resinfor use in manufacturing a wood-based composite comprises introducing awax-extender emulsion to a mixing device; introducing an adhesive resinto a mixing device; mixing the wax-extender emulsion and the adhesiveresin in the mixing device, and simultaneously co-applying the mixedwax-extender emulsion and adhesive resin to wood material for use inmanufacturing a wood-based composite.

In a feature of this aspect, the wax-extender emulsion is produced byco-emulsifying and co-homogenizing an organic extender and a waxcomponent in water. In another feature of this aspect, the adhesiveresin comprises pMDI. In yet another feature of this aspect, the mixingdevice is an in-line static mix tube.

In an additional feature of this aspect, the mixture of wax-extenderemulsion and adhesive resin is applied in the form of droplets, andwherein each droplet comprises both wax-extender emulsion and adhesiveresin. With regard to this feature, when the mixed wax-extender emulsionand adhesive resin is applied, a mixture having a 5 wt % reduction inthe amount of adhesive resin introduced to the mixing device relative tothe amount of resin introduced to the mixing device when a conventionalwax emulsion is used exhibits a comparable level of performance toseparately applied conventional wax emulsion and adhesive resin. Withfurther regard to this feature, the mixture has a 10 wt % reduction inthe amount of adhesive resin relative to that when a conventional waxemulsion is used. In addition, performance may be evaluated usingfactors selected from the group consisting of thickness swell, waterabsorption, and internal bond strength. Further, the droplets may beformed via spray or atomization.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a process for manufacturing anexemplary embodiment of a wax-extender emulsion in accordance with anaspect of the present invention.

FIG. 2 is another schematic representation of a process formanufacturing an exemplary embodiment of a wax-extender emulsion inaccordance with an aspect of the present invention.

FIG. 3 is a graphical representation of particle size distributioncurves related to Example 1.

FIG. 4A is a schematic representation of conventional wax emulsiondroplets and resin droplets applied on a wood substrate.

FIG. 4B is a schematic representation of wax-extender emulsion dropletsand resin droplets applied on a wood substrate.

FIG. 5 is a schematic diagram illustrating how a wax-extender emulsionin accordance with an aspect of the present invention and a resincomponent can be mixed and co-applied to wood furnish.

FIG. 6 is a schematic diagram representation of the distribution on woodstrands of simultaneously, co-applied resin and extended-wax emulsion asdescribed herein.

FIG. 7 is another graphical representation of particle size distributioncurves related to Example 1.

FIG. 8 is a chart showing the change in viscosity over time related tocompatibility testing in Example 4.

FIG. 9 is a chart showing TGA curves for six slack waxes in Example 6.

FIG. 10 is a chart showing the corresponding first derivative (δ) curvesof the raw data shown in FIG. 9 .

FIG. 11 is a chart correlating TGA wax volatility peaks for sixdifferent slack waxes with the COC flash point measured for the sameslack wax.

FIG. 12 is a chart showing TGA curves for a group of wax emulsions.

FIG. 13 is a chart showing the corresponding first derivative (δ) curvesof the raw data shown in FIG. 12 .

DETAILED DESCRIPTION

A wax-extender emulsion for use in the manufacture of wood-basedcomposites is described herein. The wax-extender emulsion comprises awax-extender complex suspended in water. A wax-extender complexcomprises a wax component, an organic extender component and asurfactant that surrounds and stabilizes the wax component and theorganic extender component collectively to form the wax-extendercomplex. The wax component and the organic extender component areclosely associated with one another and are stabilized by the surfactantto form the wax-extender complex.

Having the organic extender component closely associated with the waxcomponent in the wax-extender complex can provide performance advantagesfor wood-based composite products manufactured using the wax-extenderemulsion comprising the wax-extender complex. For example, thewax-extender emulsion may provide reduced wax volatility during panelproduction, may provide better distribution on wood furnish, may provideimproved compatibility with adhesive resins, may allow for thesimultaneous co-application of adhesive resins, may extend theperformance of adhesive resins, and may provide improved resistance tostatic and dynamic shear forces on the liquid emulsion during varioushandling conditions encountered during production, distribution and use.Additionally, the organic extender component offsets a portion of thewax component without diminishing moisture performance of thewax-extender emulsion. Thus, the organic extender can improve aspects ofperformance while matching or improving dimensional stability and waterabsorption performance of wood-based composites manufactured using thewax-extender emulsion.

In the wax-extender emulsion, the wax component may comprise a varietyof different wax materials. Any wax material suitable for creating awater-based emulsion can be used. The amount of wax component used inthe wax-extender emulsion varies depending on the final product use. Theway in which the final product will be used (including application andlocation) can affect viscosity and shear stability requirements for thewax-extender emulsion. Accordingly, the amount of total solids and theamount of wax component and extender component relative to one anothercan also be affected. The wax-extender emulsion may comprise 20 wt % to60 wt % wax component. Thus, the wax-extender emulsion may comprise 20wt %-55 wt %, 20 wt %-45 wt %, 22 wt %-43 wt %, 24 wt %-41 wt %, 26 wt%-40 wt %, 28 wt %-39 wt %, 29 wt %-38 wt %, and 30 wt %-37 wt % waxcomponent. For example, the wax-extender emulsion may comprise 20 wt %,22 wt %, 24 wt %, 25 wt %, 26 wt %, 27 wt %, 28 wt %, 29 wt %, 30 wt %,31 wt %, 32 wt %, 33 wt %, 34 wt %, 35 wt %, 36 wt %, 37 wt %, 38 wt %,39 wt %, 40 wt %, 45 wt %, 50 wt %, 55 wt %, or 60 wt % wax component.

The wax component can comprise a broad range of petroleum-based wax,bio-based wax, synthetic wax, additional waxes known to the relevant artor mixtures thereof. For example, the wax component may comprise a blendof two or more petroleum-based waxes, a blend of petroleum-based wax andbio-based wax, or a blend of petroleum-based wax and synthetic wax. Oneof ordinary skill in the art would be able to identify and produceblends of waxes having the desired physical properties using any ofpetroleum-based waxes, bio-based waxes, synthetic waxes, other suitablewaxes or mixtures thereof.

The term “petroleum-based wax” refers to any wax derived from oilrefining that is suitable for use as a sizing agent for wood-basedcomposites. Petroleum-based waxes can be defined by the amount of oil,microcrystalline wax and paraffinic wax that they contain. In anembodiment, the petroleum wax may be a petroleum slack wax. Slack wax isthe crude wax produced by chilling and solvent filter-pressing waxdistillate. An exemplary slack wax may comprise between 5 wt %-30 wt %oil, have a melt point below 170° F., and a flash point below 600° F.Blends of different slack waxes, along with oil, petrolatum, pureparaffinic, and scale waxes can be emulsified for use as sizing agents.

The term “biowax” refers to a broad category of animal- or plant-derivedwaxes made of unhydrogenated, partially hydrogenated and fullyhydrogenated fats and oils. Examples include partially or fullysaturated beef tallow, vegetable fats and oils, or oils derived from avariety of other plant based sources (for example, nuts, soy, sunflower,palm, corn, seeds, castor oil, or palm oil). The term “synthetic wax”generally refers to alpha olefins that are derived from polymerizedethylene or propylene.

In the wax-extender emulsion, the organic extender may includeindividual components or blends of lignocelluloses, lignin materials,lignocellulosic agricultural residue, non-lignocellulosic agriculturalmaterials (starches), lignin derivatives or mixtures thereof. As usedherein, the term “lignocelluloses” refers to the collection ofbiopolymers that make up plant material cell walls. The term“lignocelluloses” includes the three broad polymer categories that arepresent in plant cell walls, namely cellulose, hemicelluloses andlignin. As used herein, the term “lignin material” refers to one or morebyproducts of a pulping process, which is recovered during or afterpulping of lignocellulosic material. The term “lignin material” is usedbecause the lignin may be extracted in a variety of ways, each of whichcan alter the chemistry, purity, molecular weight and reactivity of thelignin. The pulp can be from any suitable lignocellulosic materialincluding hardwoods, softwoods, annual fibers, and combinations thereof.Exemplary pulping processes include kraft pulping, sulfite pulpingprocesses, organosolv pulping processes, soda pulping, enzymatichydrolysis, super critical water extraction process, and biomassdisintegration. More specific examples include kraft pulping, sulfitepulping, ASAM organosolv pulping, acid hydrolysis, Alcell® pulping,Organocell pulping, Acetosolv pulping, lignin extraction from anenzymatic hydrolysis process, super critical water extraction processand any other biomass disintegration process. In a preferred embodiment,the lignin material includes one or more byproducts of kraft pulping.For example, the lignin material may comprise dewatered kraft lignin.The term “lignocellulosic agricultural residue” refers to pulverized,ground or powder forms of agricultural residue. Lignocellulosicagricultural residue may comprise ground, pulverized, or powder forms oftree bark, wood flour, nut shells, seed hulls, corn cobbs, sugar beetresiduals, sugar cane residuals, and mixtures thereof.Non-lignocellulosic agricultural residue may comprise proteinaceous andamylaceous flours, such as wheat flour, wheat bran, corn flour, cornstarch, rice flour, and soy flour or mixtures thereof. As used herein,the term “lignin derivatives” refers to lignin material that has beenderivatized with additional chemical functional groups, such aslignosulfonates.

The organic extender is typically insoluble in water. If the extendermaterial is water-soluble (e.g., organosolv lignin materials), the watersoluble component will associate with the continuous water-phase in theemulsion. In a system where the extender is associated with thecontinuous water phase, the extender is free to migrate with the wateronce applied to wood furnish (e.g., OSB strands or particleboardfurnish), and may not remain associated with the wax. This migrationwould result in a situation where the extender cannot provide enhancedresin effectiveness at overlapping wax and resin locations.

The wax-extender emulsion can comprise from 2 wt % to 30 wt % organicextender. Thus, the wax-extender may comprise organic extender in anamount from 3 wt %-29 wt %, from 5 wt %-28 wt %, from 8 wt %-27 wt %,from 10 wt %-26 wt %, from 12 wt %-25 wt %, from 14 wt %-25 wt %, from16 wt %-24 wt %, from 16 wt %-22 wt %. For example, the emulsion maycomprise organic extender in an amount up to 5 wt %, 10 wt %, 11 wt %,12 wt %, 13 wt %, 14 wt %, 15 wt %, 16 wt %, 17 wt %, 18 wt %, 19 wt %,20 wt %, 21 wt %, 22 wt %, 23 wt %, 24 wt %, 25 wt %, 26 wt %, 27 wt %,28 wt %, 29 wt %, and 30 wt %, with a minimum concentration of 2 wt %.

The organic extender, surfactant package (also referred to as soap) andwax component combine to account for the total solids in the wax-organicextender. The wax-organic extender emulsion may comprise 30 wt % to 70wt % total solids. Thus, the wax-organic extender emulsion may comprise30 wt %-70 wt %, 32 wt %-68 wt %, 34 wt %-66 wt %, 36 wt %-64 wt %, 38wt %-62 wt %, 40 wt %-60 wt %, 42 wt %-60 wt %, 44 wt %-60 wt %, 46 wt%-60 wt %, 46 wt %-58 wt %, 46 wt %-56 wt %, 46 wt %-54 wt %, or 40%-52wt %. For example, the wax-organic extender may comprise from 30 wt % upto 32 wt %, up to 34 wt %, up to 36 wt %, up to 38 wt %, up to 40 wt %,up to 41 wt %, up to 42 wt %, up to 43 wt %, up to 44 wt %, up to 45 wt%, up to 46 wt %, up to 47 wt %, up to 48 wt %, up to 49 wt %, up to 50wt %, up to 51 wt %, up to 52 wt %, up to 53 wt %, up to 54 wt %, up to55 wt %, up to 56 wt %, up to 57 wt %, up to 58 wt %, up to 59 wt %, upto 60 wt %, up to 62 wt %, up to 64 wt %, up to 66 wt %, up to 68 wt %,or up to 70 wt % total solids.

In the wax-extender complex, the surfactant co-associates with andsurrounds the closely associated wax component and organic extendercomponent thereby forming the wax-extender complex. Any surfactantcapable of emulsifying and stabilizing the wax component and the organicextender component to form a wax-extender complex is suitable for use asa surfactant; this includes cationic, anionic and nonionic surfactants.In an exemplary embodiment, the surfactant is a reaction product of twoor more components that interact with one another to form thesurfactant. For example, surfactant components may comprise a firstsurfactant component such as a fatty acid, a lignosulfonate, or a montanwax and a second surfactant component such as an inorganic base or anorganic base that reacts with the first component to form a surfactant.For example, the emulsion surfactant may comprise the reaction productof a fatty acid and an inorganic base. A typical fatty acid structuremay include a hydrophilic, carboxylic acid head with a hydrophobic,aliphatic chain capable of complexing and forming a surfactant with abase compound. Exemplary fatty acids may include C₁₂ to C₂₂ fatty acids.Thus, the first component may include fatty acids such as lauric acid,palmitic acid, stearic acid, behenic acid, oleic acid, linoleic acid,linolenic acid, isomers thereof or mixtures thereof. The wax-extenderemulsion may comprise from 0 wt % to 5 wt % of the first component. Forexample, the wax-extender emulsion may comprise up to 0.5 wt %, 1 wt %,1.5 wt %, 2 wt %, 2.5 wt %, 3 wt %, 3.5 wt %, 4 wt %, 4.5 wt % or 5 wt %fatty acid. The second surfactant component may comprise an inorganicbase or an organic base. In an embodiment, an inorganic base maycomprise a mono-functional amine, a multi-functional amine, a cyclicamine, an alkali metal salt, an alkaline earth metal salt, ammonia orcombinations thereof. A base can be chosen based on its efficacy withthe compound being used as the first surfactant component (e.g., fattyacid). Exemplary amine bases include a tri-functional amine such astriethanolamine (TEA) and a cyclic amine such as morpholine. Additionalexemplary bases may include sodium hydroxide, potassium hydroxide,monoethanolamine (MEA), ammonia, and 2-Amino-2-Methyl-1-PropanolSolution (AMP95). The wax-extender emulsion may comprise from 0 wt % to5 wt % of the second component. For example, the wax-extender emulsionmay comprise up to 0.5 wt %, 1 wt %, 1.5 wt %, 2 wt %, 2.5 wt %, 3 wt %,3.5 wt %, 4 wt %, 4.5 wt % or 5 wt % base.

The wax-extender emulsion may also comprise a defoamer and a pHmodifier. The defoamer can reduce or release entrained air that isbrought into the emulsion by other components or through mixing. Thedefoamer may comprise a water-based defoamer, a silicone-based defoamer,a silicone-free defoamer, an oil-based defoamer, a polymer-baseddefoamer, or mixtures thereof. For example, the defoamer may comprise ablend of mineral oil and silica derivatives. The amount of defoamer maybe adjusted based on choice of defoamer and extender. In exemplaryembodiments, the defoamer may be present in the wax-extender emulsion inan amount of 0 wt % to 1 wt %. For example, defoamer may be present inamounts of up to 0.1 wt %, 0.2 wt %, 0.3 wt %, 0.4 wt %, 0.5 wt %, 0.6wt %, 0.7 wt %, 0.8 wt %, 0.9 wt %, or 1 wt % of the emulsion.

The pH modifier may comprise one or more compounds added to the emulsionproduction process at the same time or at different times. The pHmodifier can act as a pH adjuster and a dispersant. For example, the pHmodifier can aid with the consistency of the emulsion or componentsbeing mixed and with the dispersion of extender. Additionally, differentsurfactant components are more stable and perform better at different pHranges. Thus, the pH modifier can help with formation of surfactant byachieving pH conditions favoring reaction of the first surfactantcomponent and the second surfactant component. For example, when thefirst component is a fatty acid and the second component is an aminebase, other components in the wax-extender emulsion may have a pH thatalters the overall pH of the mixture, making it difficult for the fattyacid and the amine base to react completely without the addition of a pHmodifier.

The pH modifier may comprise a mono-functional amine, a multi-functionalamine, an alkali metal salt such as a metal hydroxide, an alkaline earthmetal salt or combinations thereof. For example, the pH modifier maycomprise sodium hydroxide or sodium carbonate. The amount of pH modifierused in the wax-extender emulsion is variable and can be adjusted basedon the needs of the components of the emulsion. In exemplaryembodiments, the pH modifier may be present in the wax-extender emulsionin an amount of 0 wt % to 1 wt %. For example, pH modifier may bepresent in amounts of up to 0.1 wt %, 0.2 wt %, 0.3 wt %, 0.4 wt %, 0.5wt %, 0.6 wt %, 0.7 wt %, 0.8 wt %, 0.9 wt %, or 1 wt % of the emulsion.

An exemplary embodiment of the wax-extender emulsion may comprise 30 wt% to 60 wt % petroleum-based wax, 5 wt % to 20 wt % lignin material, thereaction product of a C₁₂-C₂₀ fatty acid and a complimentarytri-functional amine as the surfactant, a blend of mineral oil andsilica derivatives, and sodium carbonate and sodium hydroxide.

The wax-extender emulsion may include additional suitable additives orcomponents, such as, for example, biocides, pigment, indicator dye,and/or wetting and dispersing agents, depending on the performance needsof the product. The wax-extender emulsion may also be formulated andused as a delivery mechanism for other components into the woodcomposite blending process, depending on need and application.

Advantageously, the process for producing the wax-extender emulsionresults in both the wax component and the organic extender componentbeing stabilized by the surfactant to form wax-extender complexparticles suspended in the continuous water phase of the emulsion. Inthe production process, the organic extender component is added to themixture to be emulsified before emulsification and homogenization. Thus,the organic extender component is emulsified with and homogenized withthe wax component. A wax-extender complex is formed prior to cooling theemulsion, and thus prior to solidification of the molten wax componentin the wax-extender complex. In contrast, extenders that are added to anemulsion after cooling and solidification are not physically able toclosely associate with the wax component.

FIG. 1 provides a schematic representation of the process for producingthe wax-extender emulsion. The process includes introducing water to thevessel or container where the emulsion will be formed, wherein the wateris at a temperature greater than the melting point of the wax component,but below the boiling point of water (35° C. to 95° C.); introducingorganic extender to the vessel; introducing the components that form theemulsion surfactant to the vessel; and introducing a molten waxcomponent to the vessel. In an exemplary embodiment, water is the firstcomponent introduced to the vessel. Those skilled in the art willrecognize that wax emulsions may be prepared with adjustments to theorder of component introduction, but that all components will be molten,homogeneously combined, and the surfactant will be present prior toemulsification, homogenization and cooling. Further, in the processdescribed herein, the extender is introduced prior to theemulsification, homogenization and cooling stages, as depicted in bothFIGS. 1 and 2 . The temperature range for molten wax varies with the waxcomponent being used. An exemplary temperature range includes 35° C. to100° C. As can be seen in FIG. 1 , pH modifier and/or defoamer may alsobe added to the vessel. Introduction of these components is optional.

The wax-extender emulsion is formed by mixing at least water, organicextender component, surfactant-forming components, and molten wax.During formation of the emulsion, the wax component, the surfactant andthe water are in the liquid phase. The molten wax component and organicextender particles are reduced in size by mixing in the presence ofsurfactant particles. The surfactant aids in homogeneously dispersingthe molten wax and organic extender in the continuous water phase atelevated temperatures and aids in preventing re-agglomeration. The waxcomponent and the organic extender component are closely associated withone another and with the surfactant, which also stabilizes the wax andextender components. A wax-extender complex, which includes a homogenousmixture of organic extender particles and wax particles surrounded andstabilized by surfactant, is formed. Because the wax particles remainmolten at this stage, the solid extender particles closely associatewith the molten wax particles.

High shear and mixing are imparted on the wax-extender emulsion whilethe emulsion is still hot thereby producing a homogenous mixture ofsimilarly sized fine molten particles of wax and fine solid particles oforganic extender. The fine molten wax particles are suspended in thecontinuous water phase. The fine, solid extender particles are suspendedin both the molten wax and continuous water phases. Exemplary high shearmixers that can be used include a high shear, single or multi-stagehomogenizer, a high-speed mixer, and a rotor-stator. Any device capableof inducing a high degree of shear and mixing on the wax-extenderemulsion is suitable for use.

The wax particles begin to solidify as the emulsion mixture cools. Thesurfactant surrounds the wax particles and the organic extenderparticles that are homogeneously sized and homogenously mixed anddispersed in the water phase thereby forming wax-extender complexedparticles comprising both wax and organic extender, which are stabilizedin the water phase.

The organic extender can be introduced to the emulsion vessel in theform of a dry powder, an agglomerated material, an organic extenderslurry, or combinations thereof. In an exemplary embodiment, a slurry ofthe organic extender may comprise water, organic extender, defoamer, andpH modifier. The water may be present in an amount from 10 wt % to 60 wt% of the extender slurry. The amount of water in the slurry can varydepending on the organic extender being used, including the moisturecontent of the extender. As discussed in greater detail above, theorganic extender may include individual components or blends oflignocelluloses, lignin materials, lignocellulosic agricultural residue,non-lignocellulosic agricultural materials, lignin derivatives ormixtures thereof. Organic extender may be present in an amount of 20 wt% to 90 wt % of the extender slurry depending at least in part on themoisture content of the extender material, the desired viscosity of theslurry, and the desired final emulsion solids and fill level. Forexample, the organic extender may be present in an amount of 20 wt % to70 wt % of the slurry. An exemplary organic extender may comprisedewatered, kraft lignin.

Defoamer is optional and may include any of the defoamers listed above,such as, for example, water-based, silicone-based, and mineral oil baseddefoamers. The defoamer may be present in an amount of up to 1 wt % ofthe extender slurry. The defoamer can be introduced to the emulsionproduction process as a component of the extender slurry, as anindependent component to the emulsion vessel, or both, depending onoperating conditions and the desired product. The pH modifier is alsooptional and may include any of the pH modifiers listed above, such as,for example, alkali salts. The pH modifier may be present in an amountof up to 1 wt % of the extender slurry. The pH modifier can beintroduced to the emulsion production process as a component of theextender slurry, as an independent component to the emulsion vessel, orboth, depending on processing needs and specific compounds used in theemulsion production process.

FIG. 2 provides an exemplary schematic representation of the process forproducing the wax-extender emulsion wherein the organic extender isadded in the form of an organic extender slurry. To prepare the organicextender slurry, the water, organic extender, defoamer, and pH modifiercan be combined in a vessel and mixed. Depending on various operatingconditions, including, for example, the type of organic extender used,combining and mixing may include imparting high shear on the mixture.For example, a homogenizer, a high-speed mixer, or a rotor-stator couldbe used to impart high shear on the extender slurry mixture.

The organic extender slurry is added to the emulsion vessel along withwater, molten wax, and surfactant forming components prior toemulsification and prior to high shear mixing. As shown in FIGS. 1 and 2, the organic extender in slurry form can be added to the emulsificationvessel at the same time in the process that organic extender in powderform can be added to the emulsification vessel.

Adding the organic extender to the emulsification vessel prior toemulsification and high shear mixing enables formation of wax-extendercomplex particles comprising both wax particles and organic extenderparticles. If organic extender is added to an emulsification mixtureafter emulsification and cooling takes place, the organic extenderparticles cannot closely associate with the wax and surfactant particlesto form the wax extender complex.

As shown with the particle size distribution curves of FIG. 3 , awax-extender emulsion wherein wax, extender, and surfactant are closelyassociated with one another has different physical characteristics thana wax emulsion wherein organic extender is not closely associated withwax and surfactant particles. FIG. 3 shows a particle size distributioncurve for an exemplary embodiment of a wax-extender emulsion.Additionally, particle size distribution curves are shown for a controlemulsion, which does not contain an extender, and a liquid solution ofthe extender material dispersed in water. As shown in FIG. 3 , thewax-extender emulsion curve has a single, narrow peak, which representsa uniform particle size distribution for the wax-extender emulsion. Asseen in FIG. 3 , the exemplary particle size for this system is around0.4 μm. The narrow and uniform particle size distribution curve exhibitsthat the organic extender is homogenously sized with and mixed with thewax component in the wax-extender emulsion. In contrast, the curvelabeled “Post Add 2D5 #3A” shows a particle size distribution curve fora system where the organic extender material was added to the samecontrol emulsion as shown in FIG. 3 , after emulsification and coolingof the wax component. Thus, the organic extender material was nothomogenized with the molten wax component in the control emulsion. ThePost Add distribution curve has a broad primary peak at 0.6 μm and asmaller secondary peak at 30 μm. Multiple peaks indicate heterogeneityin particle sizes, which suggests that the organic extender particlesare not similarly sized to the wax component particles. Homogenizing theextender material at the same time as the wax component, in the presenceof surfactant prior to cooling, helps to reduce extender particle sizeand to encourage similar sizing of wax particles and extender particles.

Conventionally, when manufacturing wood-based composites, wax emulsionsare sprayed onto wood fibers, strands or particles (or other suitablewood material used for making wood-based composites, hereaftercollectively referred to as “wood furnish”). After the water componentof the emulsion penetrates the wood or evaporates, the resulting waxdroplets remain on or near the wood surface. The effective area of eachwax droplet is related to the original particle size afterhomogenization. By co-homogenizing the organic extender and the waxcomponent prior to cooling, the organic extender is homogeneously sizedand complexed with the wax component and is thus present with each waxdroplet on the wood surface. As shown in FIGS. 4A and 4B, the presenceof organic extender with the wax droplet aids in compatibilizing the waxcomponent with adhesive resins used in manufacturing the wood-basedcomposite.

Additionally, during the manufacturing process the wood strands that aresprayed with wax emulsion are also blended with hydrophilic adhesiveresins. Conventionally, the resin component and wax component areapplied separately because of incompatibility between the two. The orderof application is interchangeable, and may be simultaneous; however,both materials are applied independently. Inevitably some resin dropletsoverlap with some wax droplets during the manufacturing process. When aconventional wax emulsion is used, the overlap locations decrease theeffective adhesion between two adjacent wood strands. In contrast, whenthe wax-organic extender emulsion is used, the hydrophilic, polarorganic extender in the wax-extender emulsion reduces the detrimentaleffect of the overlap locations thereby increasing the effectiveadhesion between two adjacent wood strands (see FIG. 4B). Thehydrophilic and polar nature of the organic extender aids incompatibilizing the wax and the resin at overlap locations.

The increased compatibility between the resin and the wax-extenderemulsion, provides manufacturing and performance benefits. For example,the wax-extender emulsion can be co-applied with resin rather thanrequiring a separate application process. Co-application providesperformance advantages and cost efficiencies that are discussed morefully below.

Combining wax emulsions and resins prior to application hastraditionally been avoided. The two systems are incompatible, which cancause reactions and emulsion instability, thereby leading to significantviscosity increase and build-up in equipment. Indeed, examples presentedbelow show a control wax emulsion is not compatible with some resins. Asshown in the examples, a mixture of the two materials readily phaseseparates, and if continually mixed, a reaction progresses, resulting ina significant viscosity increase. In contrast, the wax-extender emulsiondescribed herein can form a compatible system with a resin after mixing,thus enabling co-application of the wax-extender emulsion and the resin.Simultaneous, co-application of a wax component and resin component canimprove distribution of each individual component, which can result inmore effective coverage, and thus increased performance for both the waxcomponent and the resin.

Devices suitable for in-line mixing the wax-extender emulsion and theresin will be known to one of ordinary skill in the art. An exemplarydevice is a static mix tube. FIG. 5 provides a schematic diagramillustrating how the wax-extender emulsion and resin component can bemixed and then co-applied to wood strands or other wood furnish formanufacturing wood-based composites. As can be seen, the wax-extenderemulsion component exits holding container 2, passes through conduit 4and enters manifold 6, which then feeds the wax-extender emulsion tostatic mix tube 8. Similarly, the resin component exits holdingcontainer 10, passes through conduit 12 and enters manifold 6, whichfeeds the resin to static mix tube 8. The wax-extender emulsion andresin are intimately mixed in the static mix tube 8. The wax-extenderemulsion/resin mixture exits the static mixing tube 8 via a sprayingdevice 14, which sprays droplets containing a mixture of wax-extenderemulsion and resin onto wood strands or furnish.

FIG. 6 provides a schematic diagram illustrating the distribution onwood strands of simultaneously, co-applied resin and extended-waxemulsion. FIG. 6 can be compared to FIG. 4B, which shows thedistribution of resin and wax-extender when each component is appliedseparately. As described above, when the components are appliedseparately, the wax-extender droplets and resin droplets overlap oneanother in places. As shown in FIG. 6 , when resin and wax-extenderemulsion are simultaneously co-applied as a mixture, each sprayeddroplet contains both components thus enabling better, more completedistribution for both the wax-extender emulsion and the resin.

Distribution of a mixture of wax-extender emulsion and resin is improvedrelative to separate application of the same components. Thus, morecomplete component distribution can be achieved without increasing thevolume of components being used. For example, 10 units of resin and 10units of wax-extender emulsion can be applied separately or can besimultaneously, co-applied as a mixture. Better distribution is achievedwith the same 20 units of components when the components are applied asa mixture. In fact, distribution is improved to such an extent that whena mixture of wax-extender emulsion and resin is applied, the volume oramount of at least one of the components (for example, the resin) can bereduced without sacrificing performance. For example, the amount ofresin used may be reduced by between about 1% and about 30%. Inparticular, the amount of resin used may be reduced by about 1%, 5%,10%, 15%, 20%, 25%, or 30%. Similarly, the amount of wax-extenderemulsion used may also be reduced without sacrificing performance. Forexample, the amount of wax-extender emulsion used may be reduced bybetween about 1% and about 30%. In particular, the amount ofwax-extender emulsion used may be reduced by about 1%, 5%, 10%, 15%,20%, 25%, or 30%.

Additionally, the wax-extender emulsion provides a safety benefit duringthe wood composite manufacturing process. Wood composite manufacturersrequire waxes used during production to have a relatively lowvolatility. Volatility can be quantified by measuring the flash pointtemperature of the wax. Flash point temperature can be determined byheating a slack wax until it begins to produce a flammable vapor andthen measuring the lowest temperature at which a small test flamepassing over the surface of the wax causes the vapor to ignite. Awell-recognized and commonly used method for measuring wax flash pointis the Cleveland open-cup (COC) flash point measurement method. The COCflash point measurement is standardized as ASTM D92.

Flash point temperature requirements limit the types of slack waxes thatcan be used directly, or in water-based wax emulsions for certain woodcomposite manufacturing. Advantageously, the wax-extender emulsionsdescribed herein suppress the volatility of the wax component relativeto conventional emulsions made with the same base slack wax. Forexample, the volatility for slack wax A may be too high for the wax tobe used in certain wood composite applications (that is, slack wax A hasa low flash point temperature). Consequently, a conventional waxemulsion made with slack wax A would have higher volatility (that is,volatilize at lower temperatures). In contrast, if an exemplaryembodiment of the wax-extender emulsion described herein were preparedwith slack wax A, the volatility of slack wax A in the exemplarywax-extender emulsion would be reduced relative to the volatility ofslack wax A in a conventional wax emulsion. Reduced volatility meansthat the wax component volatilizes at a higher temperature (alsoreferred to herein as “peak wax component volatility temperature”)thereby providing increased safety. Peak wax-component volatilitytemperature is strongly correlated with wax flash point temperature.

Because of the multiple components in a water-based emulsion (forexample, water, surfactant, and wax), it can be difficult to measure theflash point for the wax component of the water-based emulsion usingtraditional methods for measuring wax flash point. Thermogravimetricanalysis (TGA) can be used to directly measure volatility anddegradation for slack waxes and water-based emulsions, providing highresolution and repeatable mass-loss versus temperature data. Forwater-based emulsions, such as the wax-extender emulsion, TGA resultscan show temperature regions corresponding with water loss, peak waxvolatility (low molecular weight (MW) components vaporize), and waxdegradation (higher MW materials break down or burn). As stated above,peak volatility temperatures correlated with flash-point data forindividual wax materials.

As shown in the example section below, for molten slack waxes, there isa correlation between the TGA peak volatility temperature and the COCflash point for the corresponding slack wax. Surprisingly, the resultsshowed that the peak wax volatility temperature for a given wax-extenderemulsion was higher than the same for the corresponding base wax in aconventional wax-emulsion. The peak volatility temperature for the waxcomponent in a wax-extender emulsion as described herein shifted higherby between about 30-40° C. (50-80° F.). Thus, the peak volatilitytemperature for the wax component in a wax-extender emulsion asdescribed herein may shift higher by about 1° to about 40° C. Withoutbeing bound by theory, this shift is believed to be due to the stronginteraction between the extender component and the wax component, whichstabilizes the low molecular weight wax component up to highertemperatures.

Comparative testing with samples having simple dilution or filling of acontrol emulsion with a non-interacting filler (for example, glassbubbles) showed no effect on the peak volatility temperature in acontrol emulsion. Additionally, comparative testing showed that adding asolution of the extender component to the wax component post emulsionformation did increase the peak wax volatility temperature, but not tothe same magnitude as a wax-extender emulsion produced as describedherein.

These results indicate that a wax-extender emulsion according to anaspect of the present invention is less volatile, and therefore safer,than conventional wax emulsions prepared with the same base slack wax.Advantageously, this feature of the wax-extender emulsion may broadenthe window of available slack wax emulsion systems that a wood compositemanufacturer can safely use and may allow for the use of highervolatility base slack waxes that are known to have better waterrepellency in a panel.

The suppressed volatility of the wax-extender emulsion may explain thethickness swell and water absorption performance benefits seen for thewax-extender emulsion. Without being bound by theory, it is surmisedthat by being complexed with the wax, the extender aids in stabilizingthe higher-volatility components in the slack-wax material, therebykeeping them in the wood composite panel and on the wood, even throughhigh temperature exposure during hot pressing.

EXAMPLES Example 1

Example 1 provides a comparison of particle size distribution curves foran exemplary embodiment of a wax-extender emulsion as described hereinand for an exemplary wax emulsion containing a post-added extenderprepared according to conventional methods. In U.S. patent applicationpublication no. 2012/0247617, the organic extender is added to the waxemulsion after the emulsion has been formed (post-added). Methodsdescribed in US 2012/0247617 were used to produce the conventional waxemulsions with post-added extender used for comparison with an exemplaryembodiment of the wax-extender emulsion described herein.

US 2012/0247617 provides several examples for formulating a wax emulsionwith post-added extender. Exemplary formulation 2D5 from Table 9 of US2012/0247617 was used because the publication indicates that thisformula was later used in OSB panel studies.

The exemplary conventional formula was prepared with the same materialsdescribed in US 2012/0247617 with the exception of the specific “ligninderivatives.” The lignin derivatives described in US 2012/0247617 wereunavailable. Instead, kraft lignin was used as the organic extendercomponent in the exemplary conventional wax emulsion. The same organicextender was used for the exemplary embodiment of the wax-extenderemulsion described herein. Using the same organic extender for both theconventional wax emulsion and the wax-extender emulsion provides a moredirect particle size comparison between the two emulsion compounds.Details not disclosed in US 2012/0247617 were estimated based onreasonable practices in the relevant field of art. Five differentversions of the 2D5 example were prepared using different assumptions.

Following formulation, each formula was measured on the HORIBA LA-950particle size analyzer, and compared against a 58% solids base waxemulsion (control), an exemplary embodiment of a wax-extender emulsiondescribed herein having 47% total solids with 20% of the solids beingorganic extender, and a water-based solution having 10 wt % of thedewatered, kraft lignin used in the exemplary emulsions. The carrierfluid for particle size analysis was distilled water.

The following materials were used in this example. CASCOWAX® EW-58S(available from Hexion) was used as the control wax-emulsion component,as this was the material used in US 2012/0247617. REAX 85A (availablefrom Ingevity) was used as the lignosulfonate as described in US2012/0247617. NaOH 50% solids caustic solution, diluted to 7.4% was usedas described in US 2012/0247617. Dried and ground kraft lignin,BioChoice™ lignin (available from Domtar) was used as the organicextender.

Example 2D5 from US 2012/0247617 was used for the post-add emulsionformulations. According to the procedure in US 2012/0247617, the stable,conventional wax emulsion was already formed when the organic extenderwas added. Some details regarding the post-add methods were not clear inUS 2012/0247617, and thus 5 different formula options were preparedbased on reasonable assumptions and/or techniques alluded to in US2012/0247617.

In US 2012/0247617, each emulsion started with a lignosulfonate (LS)solution, which was blended with 7.4% NaOH and water to form a LS-NaOHsolution. This solution was then added to the 58% solids control waxemulsion. Two points of the procedure were not clear: 1) the amount ofLS used in the LS solution, and 2) the way in which the ligninderivatives were added to the EW-58S wax.

The patent describes dissolving the LS in “ . . . a suitable amount ofwater.” Thus, three reasonable possibilities for a suitable amount ofwater were evaluated: 1) 1.8 wt % LS, 2) 3.0 wt % LS, and 3) 24.69 wt %LS (determined using back calculation from the LS-NaOH solutionproperties described in Table 7 for example 2D in US 2012/0247617).

Two methods were used to add the lignin component (“ligninderivatives”). In one method (method A), lignin in powder form was addedinto the emulsion after the LS-NaOH solution using a conventionalover-head, high-shear mixer. In the other method (method B), followingthe approach used in Example 2 of US 2012/0247617, the lignin componentwas mixed with the LS-NaOH solution at a ratio of 2 parts solution to 1part lignin solids to form a paste. The paste was then added to theemulsion at a ratio of 3 parts paste to 2 parts emulsion.

Final solids and component concentrations for the 5 exemplary samplesare provided in Table 1.

TABLE 1 Solids and component concentrations for the 5 exemplary post-addemulsion samples Measured Lignin solids Lignosulfonate component Waxsolids Sample Wt % Wt % Wt % Wt % 2D5-1A 55.32 0.04 11.97 43.98 2D5-1B50.86 0.12 20.0 23.20 2D5-2B 42.92 0.20 20.0 23.20 2D5-3A 55.55 0.5011.97 43.98 2D5-3B 42.62 1.64 20.0 23.20 Control 57.95 0.00 0.00 57.95EW-58S

The properties for formula 2D5-3A most closely match the final product2D5 described in Table 9 of US2012/0247617. These 5 samples wereanalyzed on the HORIBA particle size analyzer, and compared to thecontrol wax, the wax-extender emulsion (47% total solids, 20% of whichwere extender-solids), and the powder lignin extender used in bothwaxes. All particle size analyses were conducted in distilled water.

FIGS. 3 and 7 provide particle size distribution curves for the samplesanalyzed. FIG. 3 includes particle size distribution curves for thecontrol wax emulsion, which was also used as the base wax emulsion forall five of the Post-Add exemplary samples in Table 1. FIG. 3 alsocompares the particle size distribution curves for the wax-extenderemulsion, a 10% solution of the powder lignin material used as organicextender, and the post-add exemplary sample 2D5 #3A. FIG. 7 compares thesame 2D5 #3A curve with the other four post-add exemplary samples fromTable 1, prepared based on the teachings from US2012/0247617.

As shown in FIG. 3 , the control Cascowax EW-58S and the wax-extenderemulsion each had narrow, single-peak particle size distributionscentered at and below 1 μm, respectively. The lignin filler (BioChoice™lignin, available from Domtar) had a much larger particle size andbroader distribution. This result is believed to be due toagglomerations of lignin, which are not effectively dispersed withoutexcessively high shear, such as that generated in a homogenizer.

Approximately 20% of the solids in the wax-extender emulsion were thesame lignin as shown in the dashed-line curve for the lignin in watersolution; however, there was no discernable heterogeneity in theparticle size distribution for the wax-extender emulsion.

For the post addition sample 2D5 #3A, shown in FIG. 3 , a broad primarypeak and a smaller secondary peak were apparent. Having two peaksindicates heterogeneity in particle sizes. FIG. 7 shows the same bimodalpeak structure in each of the post addition samples listed in Table 1 asexhibited for 2D5 #3A. Each post addition sample had the same controlwax particles and lignin extender shown individually in the particlesize distribution curves; furthermore, the lignin extender was the sameas used in the 47% solids wax-extender emulsion (FIG. 3 ).

During the formation of a conventional wax emulsion, both wax and waterare liquid and hot (approximately 72-90° C.). Molten wax particles arebroken down to a fine particle size in a homogenizer and in the presenceof surfactant to prevent re-agglomeration. The surfactant associateswith the wax particles separating them from each other, and stabilizingthem in the water phase. Upon cooling, the wax particles solidify.Simply adding extender to a room-temperature emulsion comprisingsurfactant and solid wax particles cannot result in the extenderparticles closely associating with wax component particles andsurfactant in such a way to form a homogeneous wax-extender complex. Thedistribution curves in FIGS. 3 and 7 support this understanding.

Furthermore, additional potential negative effects can occur from postaddition of extender materials to a room-temperature, water-based waxemulsion. Firstly, if the extender material was water-soluble, as islikely the case with the “organosolv” lignin materials described in US2012/0247617, the water soluble component would associate with thecontinuous water-phase in the emulsion. In a system where the extenderwas associated with the continuous water phase, the extender would thusbe free to migrate with the water once applied to wood furnish (that is,OSB strands or particleboard furnish), and may not remain associatedwith the wax. Thus, the extender could not provide enhanced resincompatibility at overlapping wax and resin locations. Secondly, if theextender material comprises insoluble, solid particles that are postadded to a conventional wax emulsion, the particles could cause internalabrasion in the fluid system, and potentially damage the protectivesurfactant structures surrounding the existing wax particles.

In embodiments of the wax-extender emulsion described herein, whereinthe organic extender is lignin, during the manufacturing process, thelignin is emulsified with molten wax. The wax-extender emulsion ishomogenized to form fine, similarly sized wax-extender complexparticles. As the wax-extender emulsion cools and is solidified, thefine and similarly sized wax-extender complex particles remainhomogeneously mixed. The narrow, single-peak distribution in FIG. 3supports this understanding.

Example 2

An exemplary embodiment of a wax-extender emulsion according to anaspect of the present invention was prepared in Example 2. A stable 47wt % solids wax emulsion was prepared where 20 wt % of the wax solidswere replaced with an organic extender. This sample is referred to as“47/20”. The same exemplary formula was used in the “Wax-ExtenderEmulsion” shown in FIG. 3 . The wax component was a molten slack wax.

A pre-mix extender slurry having approximately 40% solids was preparedby passing about 1300 g water, about 5.25 g of an oil-based defoamer,about 8.75 g of sodium carbonate and about 1200 g of dewatered kraftlignin that was clumpy and approximately 60% solids through an in-line,high-shear disperser.

A wax emulsion batch kettle was filled with about 1900 g hot water at atemperature between 70-85° C. About 1600 g of the pre-mix extenderslurry was added to the batch kettle, followed by about 35 g of 50 wt %NaOH solution while agitating. About 75 g of a fatty acid and acomplimentary amount of tri-functional amine were added to the batchkettle to form the surfactant. Molten slack wax at a temperature between70-95° C. was added to the batch kettle under a moderate degree ofturbulent agitation to avoid foaming.

Following wax-extender emulsion formation, the batch was fed through adual-valve homogenizer to reduce the particle size. Exiting thehomogenizer, the wax-extender emulsion was pumped through a cooling coiland a 250 mesh filter bag. The final product properties were as follows:˜275 cps viscosity at 25° C.; pH ˜7.5, ˜47% total solids, 0.94 g/mLdensity; mean particle size <0.5 μm.

Example 3

In this example, oriented strand board (OSB) panels were prepared usingdifferent water-based emulsion systems. Sample C was an exemplarywax-extender emulsion prepared using the methods described herein, andsample A was a control water-based wax emulsion having no extender. Bothemulsions had 47% total solids. For sample C, 20% of the wax solids inthe wax-extender emulsion were replaced with extender solids beforeemulsification, according to the methods described herein. For sample A,the total solids were wax solids.

Southern pine strands were blended with 3% solids liquid phenolformaldehyde (PF) resin by wood weight in the panel face layers, and1.4% pMDI resin by wood weight in the panel core layers. The waxemulsions were applied at a 1% solids by wood weight to both the faceand core for both the control emulsion and the wax-extender emulsion.

A third condition was also prepared, in which sample A was applied at0.8% solids by wood weight (rather than 1% solids by wood weight). Thiscondition was referred to as Sample B (Δ−20% Application). All liquidapplication occurred through air spray nozzles into a rotating OSB drumblender. Panels were formed by hand, without orientation, with 27.5%bottom face strands, 45% core strands and 27.5% top face strands. Panels(22″×22″×0.5″) were pressed at 215° C. for 3 minutes to a density of 43lbs/ft³.

Thickness swell (TS), water absorption (ABS) and internal bond (IB)specimens were excised from the panels, and tested according to methodsdescribed in ASTM D 1037. The results in Table 2 show improvements inthickness swell (TS) and water absorption (ABS) for the exemplarywax-extender emulsion versus the control wax emulsion. As expected,sample B, with reduced applied wax solids, showed a decrease inthickness swell (TS) and water absorption (ABS) performance. Sample B,however, also showed the best internal bond (IB). It is surmised thatthis result was achieved because of a reduced amount of wax droplets tointerfere with resin overlap, and thus resin efficacy. Sample C hadincreased internal bond (IB) relative to Sample A, suggesting improvedcompatibility and adhesion between wax having extender and overlappingresin droplets.

TABLE 2 Combined TS, ABS and IB results for OSB panels of Example 3 TS[%] ABS [%] IB [psi] (n = 15) (n = 15) (n = 40) Treatment AVG STDEV AVGSTDEV AVG STDEV Control Wax A 19.76% 3.06% 25.09% 4.05% 65.64 19.74Emulsion Δ-20% B 21.34% 3.65% 27.56% 4.12% 85.91 25.23 ApplicationExemplary C 16.17% 2.43% 20.76% 3.05% 77.70 20.23 Wax Extend- erEmulsion

Example 4

Testing was performed to determine the compatibility between anexemplary embodiment of the wax-extender emulsion as described hereinand pMDI, which is a commonly used resin. As a control, compatibilitybetween the pMDI and a control wax emulsion was also evaluated. Both waxemulsions had 50% solids however, in the exemplary extended waxemulsion, 20% of the wax solids were replaced with organic extendersolids. The control emulsion and wax-extender emulsion were prepared inthe manner described previously. In addition to the wax-emulsionsamples, a mixture of pMDI and water and pMDI alone were also tested.

Viscosity was measured as an indicator of compatibility and stability,using a Discovery H1 viscometer (Helical geometry, 25° C., 100 s⁻¹, 3600s). Approximately 20 mL, each of the exemplary wax-extender emulsion andpMDI were simultaneously applied through a 4″×¼″ helical static mix tubedirectly into the 50 mL rheometer cup, and the test was immediatelystarted. The mixture viscosity was monitored over a 1-hour testduration. Increases in viscosity were interpreted as eitherincompatibility (wax kick-out and phase separation) or isocyanateconsumption (i.e. reactivity which could lead to pre-cure on woodstrands), or a combination of both. The same procedure was used for thecontrol wax emulsion-pMDI mixture and the water-pMDI mixture.

FIG. 8 provides a chart showing the change in viscosity over theone-hour test period. As can be seen, the control wax emulsion mixedwith pMDI showed significant growth in viscosity in a very short span oftime. Viscosity increases, such as those seen for the control waxemulsion-pMDI mixture, foreshadow complications due to equipmentbuild-up and/or pre-cure in an industrial process, thus indicating thatco-application of a control wax emulsion-pMDI mixture is not practical.Similarly, the results for water mixed with pMDI also increase, anddemonstrate an unstable mixture. Again, the reactivity of water with thepMDI isocyanate groups can lead to pre-cure and equipment build-up.However, the rheology results for the mixture of the exemplarywax-extender emulsion and pMDI indicated that the mixed wax-extenderemulsion and pMDI could be co-applied. In particular, as shown in FIG. 8, the mixed wax-extender emulsion and pMDI did not increase in viscosityfor over an hour under agitation. This behavior was similar to that seenfor pMDI alone. Additionally, testing showed that compatibility betweenthe exemplary wax-extender emulsion and pMDI was independent of the baseslack wax used in preparing the wax-extender emulsion.

Example 5

Oriented strand board (OSB) panels were produced using exemplaryembodiments of the wax-extender emulsion co-applied with pMDI, and theperformance of the OSB panels was evaluated. For comparison, OSB panelswere produced using an exemplary control wax emulsion and pMDI, whichwere applied separately.

Single-layer, non-oriented OSB panels were prepared using a 6 ft.diameter, 3 ft. deep rotary drum blender. Southern yellow pine strands(6% moisture) were tumbled at 5 RPM, such that the strands cascaded infront of two spray nozzles. The exemplary wax-extender emulsion wasmixed with the pMDI resin in-line via a 4″ long by ¼″ diameter helical,static mix-tube immediately upstream of the spray nozzles. In contrast,the control wax emulsion and pMDI were applied separately, withindependent supply lines leading directly to each spray nozzle.

Both the control emulsion and the exemplary extended wax emulsion had50% total solids; however, in the extended wax emulsion, 20% of the waxsolids were replaced with organic extender.

Four conditions in total were compared. Condition A was the controlcondition. It represented common, optimal loading levels for pMDI andwax emulsions used in industrial panels. More specifically, pMDI wasadded at 1.8% based on dry strand weight and wax emulsion was added at1.0% emulsion solids based on strand weight. In condition A, if loadinglevel were decreased for either resin or wax, moisture resistance and/ormechanical performance of the panel produced would be reduced.

Conditions B-D all included application of an exemplary embodiment of amixture of the extended wax emulsion with pMDI. The mixture in ConditionB had 1.8% pMDI and 1.0% emulsion solids by wood weight. The mixture inCondition C had 10% less pMDI resin (i.e. pMDI applied at 1.62% by woodweight) and 1.0% emulsion solids by wood weight. The mixture inCondition D had 1.62% pMDI by wood weight and 5% additional wax added(i.e. 1.05% wax-extender emulsion solids by wood weight).

During preparation, enough strands were blended per cycle to make twopanels. The total time from blending to having the second panel out ofthe press was about 45 minutes per condition. Single-layer, non-orientedpanels (22″×22″×½″) were formed by hand with a target density of 43pounds per cubic foot. One panel was pressed at a time in a 215° C.hot-press for 225 total seconds (30 s to achieve target thickness, 150 sat target thickness, and a 45 s vent stage). A silicone release agentwas applied to the caul plates before each panel. The outer 3″ perimeterof each panel was trimmed away and discarded. The remaining materialyielded three 6 inch×6 inch samples for TS and ABS testing and thirteen2 inch×2 inch samples for IB testing.

TS and IB samples were evaluated according to methods described in ASTMD 1037. IB specimen faces were lightly sanded.

Collective thickness swell (TS), water absorption (ABS) and internalbond strength (TB) results are presented in Table 3. Statisticalanalyses determined there were no significant differences in TS, ABS orIB results between each condition. Thus, panels produced with theexemplary wax-extender emulsion, which embodied 20% less wax solids,performed at least as well as panels produced with un-extended controlwax. In the case of conditions C & D, the reduction in pMDI did notreduce panel strength or moisture durability

TABLE 3 Combined TS, ABS and IB results Example 5. TS [%] ABS [%] IB[psi] (n = 6-12) (n = 6-12) (n = 25-52) Treatment Code AVG STDEV AVGSTDEV AVG STDEV Control - Separate - 1.8% A 13.96% 2.01% 15.63% 1.98%124.84 27.87 Extended - Co-Applied - 1.8% B 13.50% 1.17% 14.82% 1.46%124.89 30.37 Extended - Co-Applied - 1.62% C 13.41% 0.99% 15.26% 1.92%130.18 22.65 Extended - Co-Applied - 1.62% + D 12.45% 0.95% 14.72% 1.29%129.04 19.58 5% additional wax (1.05%)

While, significant differences were not detected between any of theconditions, the results show that using a wax-extender emulsion appliedas a mixture with pMDI as described herein improved TS relative toseparately applied, un-extended control wax. Furthermore, no increase inTS was observed even with the sample having a 10% pMDI reduction.Additionally, adding 5% additional wax appeared to reduce further theTS, even with a 10% reduction in pMDI.

Table 3 also shows that simultaneously, co-applying the wax-extenderemulsion as a mixture with pMDI met or exceeded the mean IB valuesrelative to the control, even with reduced resin addition. This providesevidence that co-application of wax-extender emulsion and resin as amixture provides improved distribution, and thus resin efficiency.

The evaluation showed that co-application of wax-extender emulsion andpMDI as a mixture can allow for, at least, a 10% reduction in pMDI whilemeeting or exceeding control performance for TS, ABS and IB. Theperformance results for the mixture were at least comparable to controlperformance.

Example 6

Thermogravimetric Analysis (TGA) was performed to evaluate volatility ofexemplary embodiments of the wax-extender emulsion described herein.Samples of different slack waxes were compared using the TGA methodalongside the Cleveland Open Cup (COC) flash point method described inASTM D 92. The COC method is typically used as a screening tool todetermine the volatility, and thus safety, for different slack waxsystems. It is inherently difficult to measure the flash point for awater-based wax emulsion, and thus the base slack wax flash point isoften used to describe the emulsions made from the base waxes. However,the TGA method provides a direct measurement of volatility.

Testing showed a strong correlation between the peak temperaturecorresponding to the wax volatility observed in the TGA data, and theflash point detected with the COC method. After establishing thecorrelation, the TGA data was used to show that the presence of theextender in the wax-extender emulsion increased the temperaturecorresponding with the wax volatility. It was further demonstrated thatvolatility suppression is unique to the extender being complexed withthe wax particles during emulsion formation. This result wasdemonstrated by samples having post added fillers. The post addedfillers included the same extender material that was used in theexemplary embodiment of the wax-extender emulsion and 3M™ glass bubblesS32 in water.

Slack wax samples (3 g±1 g material) were placed on a glass-fiber paper,on an aluminum pan in a Computrac Max 5000 XL, and ramped at 5°C./minute from 50° C. to 600° C. Raw data and the first derivative ofweight loss with respect to temperature were plotted for each sample,and are shown in FIGS. 9 and 10 , respectively. The raw TGA data in FIG.9 shows that the different waxes begin to degrade above 280° F. Thecorresponding first derivative (δ) curves in FIG. 10 show a distinct,sharp peak, corresponding to the loss of mass in the raw data. This peakis hereinafter referred to as the “wax volatility peak”. Comparisonswere made between the slack wax TGA peak temperatures relative to theslack wax flash points measured with the COC method (ASTM D92).

FIGS. 9 and 10 also show TGA data for a 40% suspension of extender inwater. This curve is included to demonstrate that the degradationtemperature for the extender material is easily distinguishable from thewax volatility peak.

The TGA wax volatility peaks for the exemplary emulsions are plottedrelative to the COC flash point for the corresponding slack wax from theexemplary emulsions in FIG. 11 . The correlation (R²=0.9715) shows thatTGA data can be used to effectively describe volatility of the waxmaterial in the wax-extender emulsion, in compliment with the flashpoint data. Furthermore, the TGA data can be used to directly measurewax volatility in an emulsion.

Additional testing was performed for four wax emulsion samples. Onesample was a control wax emulsion with no extender. One sample was anexemplary embodiment of a wax-extender emulsion in accordance with anaspect of the present invention, wherein the extender replaced 20% ofthe wax solids. A third sample was a wax emulsion with extender addedafter emulsification and cooling, wherein the extender replaced 20% ofthe wax solids. The last sample was a wax emulsion wherein glass beadswere used as filler. FIGS. 12 and 13 show wax emulsion TGA curves forthe four wax emulsion samples. FIG. 12 illustrates raw data, and FIG. 13illustrates the first derivative curve of mass loss with respect totemperature. The figures demonstrate that as the temperature increased,water evaporated first, followed by a plateau region corresponding withthe emulsion solids. At still higher temperatures (above 280° F.), thewax component began to volatilize, and the wax volatility peak was againapparent (FIG. 13 ), just as was observed in the slack wax data (FIG. 10).

The control wax emulsion TGA data shows a wax volatility peak at 366.8°F. The exemplary embodiment of the wax-extender emulsion was preparedwith the same base slack wax as the control emulsion. The exemplarywax-extender emulsion had a wax volatility peak of 445.4° F.,demonstrating volatility suppression of greater than 78° F. (FIG. 13 ).

These results suggest that the extender material in the wax-extenderemulsion is closely associated with the wax component, in a manner thatis only achieved by co-homogenization at the time of emulsification. Infact, the results of testing showed that post addition of the sameextender material does not provide the same magnitude of effect on thewax volatility peak. As shown in FIG. 13 , the sample wherein the sameextender material was added to the wax emulsion after emulsification andcooling, did increase the wax volatility peak, but only by 48° F. (FIG.13 ). A reduced effect was expected because the wax material in thecontrol emulsion was already solidified following emulsification andcooling by the time the extender was added. Thus, the post addedextender could not closely associate with an already solidified waxmoiety.

Without being bound by theory, it is believed that for the wax-extenderemulsion described herein, the extender closely associates with andinteracts with the wax component thereby stabilizing the low molecularweight wax material. As shown in FIGS. 12 and 13 , adding glass bubbles,which are a non-reactive filler, after emulsification and cooling, hadno effect on the wax volatility peak (FIG. 13 ).

The invention claimed is:
 1. A wax-extender emulsion comprising awax-extender complex suspended in water, wherein the wax-extendercomplex comprises a wax component, an organic extender component and asurfactant, wherein the surfactant associates with and stabilizes thewax component and the organic extender component, which are associatedwith one another, to form the complex, wherein the wax-extender emulsioncomprises from 2 wt % to 30 wt % organic extender.
 2. The wax-extenderemulsion of claim 1, wherein the wax component comprises apetroleum-based wax, a bio-based wax, a synthetic wax or mixturesthereof.
 3. The wax-extender emulsion of claim 2, wherein thepetroleum-based wax comprises slack wax.
 4. The wax-extender emulsion ofclaim 3, wherein the slack wax comprises between 5 wt % to 30 wt % oil,having a melting point below 170° F. and a flash point below 600° F. 5.The wax-extender emulsion of claim 3, wherein the petroleum-based waxfurther comprises oil, petrolatum, pure paraffinic, microcrystalline,scale waxes, or combinations thereof.
 6. The wax-extender emulsion ofclaim 1, wherein the organic extender comprises a lignin material. 7.The wax-extender emulsion of claim 6, wherein the lignin materialcomprises one or more byproducts of a pulping process, wherein thepulping process is selected from the group consisting of kraft pulping,sulfite pulping, ASAM organosolv pulping, acid hydrolysis, soda pulping,Organocell pulping, Acetosolv pulping, and combinations thereof.
 8. Thewax-extender emulsion of claim 6, wherein the lignin material comprisesone or more byproducts of kraft pulping.
 9. The wax-extender emulsion ofclaim 1, wherein the emulsion comprises 20 wt % to 60 wt % waxcomponent.
 10. The wax-extender emulsion of claim 1, wherein theemulsion comprises 30 wt % to 70 wt % combined wax component and organicextender.
 11. The wax-extender emulsion of claim 1, wherein the emulsionsurfactant comprises the reaction product of a fatty acid and a base.12. The wax-extender emulsion of claim 11, wherein the fatty acidcomprises a C₁₂ to C₂₂ fatty acid.
 13. The wax-extender emulsion ofclaim 11, wherein the fatty acid comprises lauric acid, palmitic acid,stearic acid, behenic acid, oleic acid, linoleic acid, linolenic acid,isomers thereof or mixtures thereof.
 14. The wax-extender emulsion ofclaim 11, wherein the fatty acid accounts for up to 5 wt % of the waxemulsion.
 15. The wax-extender emulsion of claim 11, wherein the basecomprises a mono-functional amine, a multi-functional amine, cyclicamine, an alkali metal salt, an alkaline earth metal salt, ammonia orcombinations thereof.
 16. The wax-extender emulsion of claim 11, whereinthe base accounts for up to 5 wt % of the wax emulsion.
 17. Thewax-extender emulsion of claim 1, further comprising a defoamer and a pHmodifier.
 18. The wax-extender emulsion of claim 17, wherein thedefoamer comprises a water-based defoamer, a silicone-based defoamer, asilicone-free defoamer, an oil-based defoamer, a polymer-based defoamer,or mixtures thereof.
 19. The wax-extender emulsion of claim 17, whereinthe pH modifier comprises a mono-functional amine, a multi-functionalamine, an alkali metal salt, an alkaline earth metal salt orcombinations thereof.
 20. The wax-extender emulsion of claim 17,comprising 30 wt % to 60 wt % petroleum-based wax as the wax componentand 5 wt % to 20 wt % lignin material as the organic extender, whereinthe emulsion surfactant comprises the reaction product of a C₁₂-C₂₀fatty acid and a complimentary tri-functional amine, the defoamercomprises a nonionic blend of mineral oil and silica derivatives, andthe pH modifier comprises sodium carbonate and sodium hydroxide.
 21. Thewax-extender emulsion of claim 1, wherein a particle size distributioncurve for the wax-extender emulsion has a single, uniform peak.
 22. Thewax-extender emulsion of claim 1, wherein a peak wax volatilitytemperature of the wax component in the wax-extender emulsion is higherthan a peak wax volatility temperature of a control wax emulsionutilizing a corresponding base slack wax material.
 23. The wax-extenderemulsion of claim 22, wherein the peak wax volatility temperature of thewax component in the wax-extender emulsion is between about 1° C. and40° C. higher than the peak wax volatility temperature of a control waxemulsion utilizing a corresponding base slack wax material.
 24. Thewax-extender emulsion of claim 23, wherein the peak wax volatilitytemperature of the wax component in the wax-extender emulsion is betweenabout 20° C. and 40° C. higher than the peak wax volatility temperaturea control wax emulsion utilizing a corresponding base slack waxmaterial.
 25. A method of simultaneously co-applying a mixture of awax-extender emulsion and an adhesive resin for use in manufacturing awood-based composite, comprising: a) introducing a wax-extender emulsionto a mixing device, the wax-extender emulsion comprising a wax-extendercomplex suspended in water, wherein the wax-extender complex comprises awax component, an organic extender component and a surfactant, whereinthe surfactant associates with and stabilizes the wax component and theorganic extender component, which are closely associated with oneanother, to form the complex, wherein the wax-extender emulsioncomprises from 2 wt % to 30 wt % organic extender; b) introducing anadhesive resin to a mixing device; c) mixing the wax-extender emulsionand the adhesive resin in the mixing device, and d) simultaneouslyco-applying the mixed wax-extender emulsion and adhesive resin to woodmaterial for use in manufacturing a wood-based composite.
 26. The methodof claim 25, wherein the wax-extender emulsion is produced byco-emulsifying and co-homogenizing an organic extender and a waxcomponent in water.
 27. The method of claim 25, wherein the adhesiveresin comprises pMDI.
 28. The method of claim 25, wherein the mixingdevice is an in-line static mix tube.
 29. The method of claim 25,wherein the mixture of wax-extender emulsion and adhesive resin isapplied in the form of droplets, and wherein each droplet comprises bothwax-extender emulsion and adhesive resin.
 30. The method of claim 29,wherein when the mixed wax-extender emulsion and adhesive resin isapplied, a mixture having a 5 wt % reduction in the amount of adhesiveresin introduced to the mixing device relative to the amount of resinintroduced to the mixing device when a conventional wax emulsion is usedexhibits a comparable level of performance to separately appliedconventional wax emulsion and adhesive resin.
 31. The method of claim30, wherein the mixture has a 10 wt % reduction in the amount ofadhesive resin relative to that when a conventional wax emulsion isused.
 32. The method of claim 29, wherein performance is evaluated usingfactors selected from the group consisting of thickness swell, waterabsorption, and internal bond strength.
 33. The method of claim 29,wherein the droplets are formed via spray or atomization.
 34. Thewax-extender emulsion of claim 1, wherein the wax component and theorganic extender component of the wax-extender complex areco-homogenized and co-emulsified.
 35. The wax-extender emulsion of claim1, wherein the emulsion is capable of being mixed with an adhesive suchthat the emulsion and adhesive are simultaneously co-applied.